Question

calculate the arithmetic mean:
age group: 14-15 16-17 18-20 21-24 25-29 30-34 35-39
no.of wage earners: 60 140 150 110 110 100 90

Answer 1

its difficult to calculate the mid value here coz the common difference is changing

Answer 2

hmm
don't we hve to add all the numbers and divide by the number of numbers

Answer 3

tag ganeshie8 or freckles

Answer 4

@madhu.mukherjee.946

Answer 5

@ganeshie8 @freckles

Answer 6

@Nnesha is right

Answer 7

just add the numbers and divide by the number of numbers

Answer 8

no in group frequency we don't solve it like that way

Answer 9

oh I see
the mid value is just the sum of endpoints and that result divided by 2

Answer 10

for example:
\[\frac{14+15}{2}=\frac{29}{2}=14.5\]

Answer 11

so x_1=14.5
and f_1=60
x_1*f_1=14.5*60

Answer 12

\[\text{ mean }=\frac{x_1 f_1 +x_2 f_2 +x_3 f_3+x_4f_4+x_5f_5+x_6f_6+x_7f_7}{f_1+f_2+f_3+f_4+f_5+f_6+f_7} \\ \]

Answer 13

at least that is my definition of midpoint http://www.yale.edu/ynhti/curriculum/units/1986/5/86.05.03.x.html
here they pick the midpoint of 99 to 100 as 98 which is odd because that is not the midpoint of 99 to 100

Answer 14

https://www.google.com/url?sa=t&rct=j&q=&esrc=s&source=web&cd=2&cad=rja&uact=8&ved=0CCYQFjABahUKEwi65aKC-c7HAhXGe5IKHe0GCyQ&url=http%3A%2F%2Fwww.ncert.nic.in%2Fncerts%2Fl%2Fjemh114.pdf&ei=Gv3hVbrwCsb3yQTtjaygAg&usg=AFQjCNHJrODzYQJjv0n7Hewgqz1FdTeu8g&sig2=y8vTO034h9vpbuUPodRU_Q
page 269 contains classes with unequal width

Answer 15

thank you so much

Answer 16

@madhu.mukherjee.946
still trying to figure out how to pick h

so I think I will choose a to be that thingy there
because it looks like they are picking a to be one of the "middle numbers"
and we only have one middle here since we have an odd amount of data entries

do you ever seen this method? And do you know how to pick h?